Lubricating oils have been used in the past to lubricate the bearings of positive displacement compressors, to seal the rotors, and to cool the compressed gases. Lubricating oils typically used in the industry comprise a mineral oil or synthetic oil as a base oil, and various additives for a particular purpose. Oxidation stability and varnish and deposit control are some of the important properties desirable in a lubricant for maximizing-the life of the lubricant, and hence, the life of the equipment, especially under the high temperature and pressure conditions created when operating a positive displacement compressor, such as a reciprocating rotary vane, scroll, or rotary screw air compressor.
It has also been desirable in the industry to provide a lubricating composition which does not deteriorate due to high temperatures. Thermal stability of a lubricating oil is therefore sought after. There is also a need for a lubricating composition exhibiting demulsibility and hydrolytic stability, particularly under high temperature and pressure conditions.
Japanese Patent No. 2-286792, published on Nov. 26, 1990, is directed to preventing oxidation deterioration; Specifically, it relates to a lubricating oil composition comprising, as an essential component, 1-naphthol, blended in a base oil containing 5% by weight or more of an alkyl naphthalene. Japanese Patent No. 2-286792 forms a 1-naphthol/alkyl aromatic blend, and adds this blend to any material suitable for use as a lubricating oil.